Sensors may be used to collect real-time data of properties for an object to which the sensor is attached. Included among various applications of sensors used to collect real-time data are those associated with the collection of physiological patient data that may be used to perform medical diagnostics. For example, biosensors, which may be implanted, attached, or otherwise disposed on a patient such as on the skin, may be used to gather physiological data about a patient. That data may be wirelessly transmitted in a continuous manner and may be used to initiate medical care if an abnormal condition is detected. In some sensor systems, collected data may be selectively transmitted when triggered by detection of some condition including, for example, the detection of characteristics of abnormal patient physiology.
Particularly, where large amounts of data may be collected using a sensor and/or where a sensor is designed for long term use without recharging, it may be important to conserve energy available in the sensor including energy that may be used in associated with data transmission. Monitoring data may, for example, be transmitted to a collection station using wireless communication typically via low power radio-frequency (RF) communication. However, low-power signaling may limit the transmission range of a sensor to a specific locality. Accordingly, it may be useful to track a sensor's position to become aware of when the sensor may be moving out of that locality and a range where transmission may be effective. Tracking a sensor system may include identification of whether a sensor is communicating with another device by exchanging signals between the devices. Particularly, a message may be sent to or from a sensor and communication station with one device sending a message to another and waiting for a response. That is, a protocol for sending one or more signals or “pings” may be implemented. However, energy consumption associated with both receiving and transmitting of such signals may also be significant.
There remains a need for systems and methods that minimize the consumption of power used to track communication with a remote sensor. There is also a need for systems that may be used to transmit data based on the position of a sensor within a monitoring locale and/or to transmit data before it may be lost or become inaccessible if a sensor loses communication. For example, there is a need for systems configured to select, prioritize, and/or trigger exchange of information between a mobile device and a remote collection station as a device may approach a monitoring boundary and/or as communication strength drops.